The present invention relates to new compounds, in particular to new 4,4xe2x80x2-diaminostilbene-2,2xe2x80x2-disulfonic acid compounds which are useful as fluorescent whitening agents or for inhibiting (quenching) the effect of anionic fluorescent whitening agents on substrates.
In WO 96/00221, there are described optical brightening agents for textiles, paper etc. The disclosed compounds have the formula: 
in which Ra and Rb are the same or different and each has the formula xe2x80x94NRcRd in which Rc is hydrogen; C1-C6alkyl which is optionally substituted by at least one of mercapto, C1-C6thioalkyl, OH and SO3Mxe2x80x2 in which Mxe2x80x2 is hydrogen, a colourless cation or an amine-derived cation; or xe2x80x94Re(CO2Mxe2x80x2)x in which Re is an aliphatic moiety having 1-6 carbon atoms, those valencies not bonded with groups CO2Mxe2x80x2 being bonded with at least one of hydrogen, mercapto, C1-C6thioalkyl, OH and SO3Mxe2x80x2 in which Mxe2x80x2 has its previous significance and x is an integer from 1 to 4, provided that, when Rc is C1-C6alkyl which is optionally substituted by at least one of mercapto, C1-C6thioalkyl, OH and SO3Mxe2x80x2, Rc is substituted with at least both of OH and SO3Mxe2x80x2; Rd is Rc, hydrogen or C3-C6alkyl, provided that Rc and Rd cannot both be hydrogen and that, when one of Rc and Rd is hydrogen, the other cannot be xe2x80x94(NHCH2CO2H); or Rc and Rd, together with the nitrogen atom, form a ring having from 5-6 members only, one of which is heterocyclic, which ring is singly substituted with xe2x80x94COOMxe2x80x2 or xe2x80x94SO3Mxe2x80x2; and each Rf, independently, is hydrogen, methyl, C1-C6alkoxy or halogen.
A new class of 4,4xe2x80x2-diaminostilbene-2,2xe2x80x2-disulfonic acid compounds has now been found most of which are useful as fluorescent whitening agents and which have superior properties with respect to the compounds disclosed in WO 96/00221, and others of which are useful for inhibiting (quenching) the effect of anionic fluorescent whitening agents on substrates.
Accordingly, the present invention provides new compounds having the formula: 
in which X is O or, preferably, NH; M is hydrogen, an alkali metal atom, ammonium or a cation formed from an amine; each R1, independently, is an aminoacid residue from which a hydrogen atom on the amino group has been removed; n is 1 or 2; and each R2, independently, is hydrogen, C1-C3alkyl, halogen, cyano, COOR in which R is hydrogen or C1-C3alkyl, CONHxe2x80x94R in which R has its previous significance, SO2NHxe2x80x94R in which R has its previous significance, NHxe2x80x94COR in which R has its previous significance, SO3M in which M has its previous significance or, when n is 1, R2 can also be COxe2x80x94R3 in which R3 is C1-C3alkyl or phenyl;
provided that those compounds are excluded in which
a) X is NH, n is 1 and R2 is SO3M in which M has its previous significance; or
b) X is NH, n is 2 and one R2 is SO3M in which M has its previous significance, and the other R2 is hydrogen, methyl or halogen; or
c) X is NH, n is 1, R1 is glycine and R2 is H or CO2H; or
d) X is NH, n is 2, each R2 is SO3M in which M has its previous significance and the SO3M groups are in 2,5-positions in the phenyl ring and R1 is D,L-alanine, L-valine, L-leucine, L-isoleucine, L-threonine, L-aspartic acid, L-glutamic acid, L-phenylalanine, L-proline, D,L-methionine or glycine.
Preferably M is hydrogen, Na, K, Ca, Mg, ammonium, mono-, di-, tri- or tetra-C1-C4alkylammonium, mono-, di- or tri-C1-C4hydroxyalkylammonium or ammonium that is di- or tri-substituted with a mixture C1-C4alkyl hydroxyalkyl groups. Preferably each M is Na.
A halogen substituent R2 may be fluorine, bromine or iodine but is preferably chlorine.
In the compounds of formula (1), n is preferably 1 and R2 is preferably hydrogen, methyl, chlorine, cyano, COOH, COO-methyl, CONH2, CONH-methyl, SO2NH2, SO2NH-methyl or NH-COmethyl.
Preferably, each of the aminoacid residues R1 is the same. Examples of preferred aminoacid residues R1 include those having the formula xe2x80x94NHxe2x80x94CH(CO2H)xe2x80x94R3 in which R3 is hydrogen or a group having the formula xe2x80x94CHR4R5 in which R4 and R5, independently, are hydrogen or C1-C4alkyl optionally substituted by one or two substituents selected from hydroxy, thio, methylthio, amino, carboxy, sulfo, phenyl, 4-hydroxyphenyl, 3,5-diiodo-4-hydroxyphenyl, xcex2-indolyl, xcex2-imidazolyl and NHxe2x95x90C(NH2)NHxe2x80x94.
Specific examples of aminoacids from which such preferred aminoacid residues R1 are derived include glycine, alanine, sarcosine, serine, cysteine, phenylalanine, tyrosine (4-hydroxyphenylalanine), diiodotyrosine, tryptophan (xcex2-indolylalanine), histidine ((xcex2-imidazolylalanine), xcex1-aminobutyric acid, methionine, valine (xcex1-aminoisovaleric acid), norvaline, leucine (xcex1-aminoisocaproic acid), isoleucine (xcex1-amino-xcex2-methylvaleric acid), norleucine (xcex1-amino-n-caproic acid), arginine, ornithine (xcex1,xcex4-diaminovaleric acid), lysine (xcex1,xcex5-diaminocaproic acid), aspartic acid (aminosuccinic acid), glutamic acid (xcex1-aminoglutaric acid), threonine, hydroxyglutamic acid and taurine, as well as mixtures and optical isomers thereof. Of these aminoacids from which such preferred aminoacid residues R1 are derived, sarcosine, taurine, glutamic acid and aspartic acid are particularly preferred.
A further preferred example of an aminoacid from which an aminoacid residue R1 may be derived is iminodiacetic acid.
Other, less preferred examples of aminoacids from which aminoacid residues R1 may be derived include cystine, lanthionine, proline and hydroxyproline.
In addition to the above-mentioned preferred classical aminoacids, R1 may also be the residue of an aromatic aminoacid such as p-aminobenzoic acid or o-aminobenzoic acid.
In the compounds of formula (1), when n is 1 and each R2 is COxe2x80x94R3 in which R3 is C1-C3alkyl or phenyl, preferably methyl, such compounds are not useful as fluorescent whitening agents, rather they are are useful for inhibiting (quenching) the effect of anionic fluorescent whitening agents on substrates.
The compounds of formula (1) may be produced by reacting, under known reaction conditions, cyanuric chloride, successively, in any desired sequence, with each of 4,4xe2x80x2-diamino-2,2xe2x80x2-stilbene disulfonic acid, an amino compound capable of introducing a group 
in which R2 and n have their previous significance, and a compound capable of introducing a group R1, in which R1 has its previous significance.
The starting materials are known compounds which are readily available.
Most of the compounds of formula (1) are excellent fluorescent whitening agents for substrates such as textiles and, in particular, for paper.
Accordingly, the present invention provides a method for the fluorescent whitening of a substrate comprising contacting the substrate with a compound having the formula (1A): 
in which X is O or NH; M is hydrogen, an alkali metal atom, ammonium or a cation formed from an amine; each R1, independently, is an aminoacid residue from which a hydrogen atom on the amino group has been removed; n is 1 or 2; and each Rxe2x80x22, independently, is hydrogen, C1-C3alkyl, halogen, cyano, COOR in which R is hydrogen or C1-C3alkyl, CONHxe2x80x94R in which R has its previous significance, SO2NHxe2x80x94R in which R has its previous significance, NHxe2x80x94COR in which R has its previous significance or SO3M in which M has its previous significance;
provided that those compounds are excluded in which X is NH, n is 2 and one R2 is SO3M in which M has its previous significance, and the other R2 is hydrogen, methyl or halogen.
When used for the fluorescent whitening of paper, the compound of formula (1A) according to the present invention may be applied to the paper substrate in the form of a paper coating composition, or directly in the size press.
In one preferred aspect, the present invention provides a method for the fluorescent whitening of a paper surface, comprising contacting the paper surface with a coating composition comprising a white pigment; a binder dispersion; optionally a water-soluble co-binder; and sufficient of a fluorescent whitening agent having the formula (1A) according to the present invention, to ensure that the treated paper contains 0.01 to 1% by weight, based on the white pigment, of a fluorescent whitening agent having the formula (1A).
As the white pigment component of the paper coating composition used according to the method of the present invention, there are preferred inorganic pigments, e.g., aluminium or magnesium silicates, such as China clay and kaolin and, further, barium sulfate, satin white, titanium dioxide , calcium carbonate (chalk) or talcum; as well as white organic pigments.
The paper coating compositions used according to the method of the present invention may contain, as binder, inter alia, plastics dispersions based on copolymers of butadiene/styrene, acrylonitrile/butadiene/styrene, acrylic acid esters, acrylic acid esters/styrene/acrylonitrile, ethylene/vinyl chloride and ethylene/vinyl acetate; or homopolymers, such as polyvinyl chloride, polyvinylidene chloride, polyethylene and polyvinyl acetate or polyurethanes. A preferred binder consists of styrene/butyl acrylate or styrene/butadiene/acrylic acid copolymers or styrene/butadiene rubbers. Other polymer latices are described, for example, in U.S. Pat. Nos. 3,265,654, 3,657,174, 3,547,899 and 3,240,740.
The optional water-soluble protective colloid may be, e.g., soya protein, casein, carboxymethylcellulose, natural or modified starch, chitosan or a derivative thereof or, especially, polyvinyl alcohol. The preferred polyvinyl alcohol protective colloid component may have a wide range of saponification levels and molecular weights; e.g. a saponification level ranging from 40 to 100; and an average molecular weight ranging from 10,000 to 100,000.
Recipes for coating compositions for paper are described, for example, in J. P. Casey xe2x80x9cPulp and Paperxe2x80x9d; Chemistry and Chemical Technology, 2nd edition, Volume III, pages 1684-1649 and in xe2x80x9cPulp and Paper Manufacturexe2x80x9d, 2nd and 5th edition, Volume II, page497 (McGraw-Hill).
The paper coating compositions used according to the method of the present invention preferably contain 10 to 70% by weight of a white pigment. The binder is preferably used in an amount which is sufficient to make the dry content of polymeric compound up to 1 to 30% by weight, preferably 5 to 25% by weight, of the white pigment. The amount of fluorescent brightener preparation used according to the invention is calculated so that the fluorescent brightener is preferably present in amounts of 0.01 to 1% by weight, more preferably 0.05 to 1% by weight, and especially 0.05 to 0.6% by weight, based on the white pigment.
The paper coating composition used in the method according to the invention can be prepared by mixing the components in any desired sequence at temperature from 10 to 100xc2x0 C., preferably 20 to 80xc2x0 C. The components here also include the customary auxiliaries which can be added to regulate the rheological properties, such as viscosity or water retention capacity, of the coating compositions. Such auxiliaries are, for example, natural binders, such as starch, casein, protein or gelatin, cellulose ethers, such as carboxyalkylcellulose or hydroxyalkylcellulose, alginic acid, alginates, polyethylene oxide or polyethylene oxide alkyl ethers, copolymers of ethylene oxide and propylene oxide, polyvinyl alcohol, water-soluble condensation products of formaldehyde with urea or melamine, polyphosphates or polyacrylic acid salts.
The coating composition used according to the method of the present invention is preferably used to produce coated printed or writing paper, or special papers such as cardboard or photographic papers.
The coating composition used according to the method of the invention can be applied to the substrate by any conventional process, for example with an air blade, a coating blade, a roller, a doctor blade or a rod, or in the size press, after which the coatings are dried at paper surface temperatures in the range from 70 to 200xc2x0 C., preferably 90 to 130xc2x0 C., to a residual moisture content of 3-8%, for example with infra-red driers and/or hot-air driers. Comparably high degrees of whiteness are thus achieved even at low drying temperatures.
By the use of the method according to the invention, the coatings obtained are distinguished by optimum distribution of the dispersion fluorescent brightener over the entire surface and by an increase in the level of whiteness thereby achieved, by a high fastness to light and to elevated temperature (e.g. stability for 24 hours at 60-100xc2x0 C.) and excellent bleed-fastness to water.
In a second preferred aspect, the present invention provides a method for the fluorescent whitening of a paper surface comprising contacting the paper in the size press with an aqueous solution containing a size, optionally an inorganic or organic pigment and 0.1 to 20 g/l of a fluorescent whitening agent having the formula (1A). Preferably, the size is starch, a starch derivative or a synthetic sizing agent, especially a water-soluble copolymer.
The present invention also provides, as a third aspect, a method for the improvement of the SPF of a textile fibre material, comprising treating the textile fibre material with 0.05 to 3.0% by weight, based on the weight of the textile fibre material, of one or more compounds having the formula (1A) as hereinbefore defined.
Textile fibres treated according to the method of the present invention may be natural or synthetic fibres or mixtures thereof. Examples of natural fibres include vegetable fibres such as cotton, viscose, flax, rayon or linen, preferably cotton and animal fibres such as wool, mohair, cashmere, angora and silk, preferably wool. Synthetic fibres include polyester, polyamide and polyacrylonitrile fibres. Preferred textile fibres are cotton, polyamide and wool fibres.
Preferably, textile fibres treated according to the method of the present invention have a density of less than 200 g/m2 and have not been previously dyed in deep shades.
Some of the compounds of formula (1A) used in the method of the present invention may be only sparingly soluble in water and may need to be applied in dispersed form. For this purpose, they may be milled with an appropriate dispersant, conveniently using quartz balls and an impeller, down to a particle size of 1-2 microns.
As dispersing agents for such sparingly-soluble compounds of formula (1A) there may be mentioned:
acid esters or their salts of alkylene oxide adducts, e.g., acid esters or their salts of a polyadduct of 4 to 40 moles of ethylene oxide with 1 mole of a phenol, or phosphoric acid esters of the adduct of 6 to 30 moles of ethylene oxide with 1 mole of 4-nonylphenol, 1 mole of dinonylphenol or, especially, with 1 mole of compounds which have been produced by the addition of 1 to 3 moles of styrenes on to 1 mole of phenol;
polystyrene sulphonates;
fatty acid taurides;
alkylated diphenyloxide-mono- or -di-sulphonates;
sulphonates of polycarboxylic acid esters;
addition products of 1 to 60, preferably 2 to 30 moles of ethylene oxide and/or propylene oxide on to fatty amines, fatty amides, fatty acids or fatty alcohols, each having 8 to 22 carbon atoms, or on to tri- to hexavalent C3-C6alkanols, the addition products having been converted into an acid ester with an organic dicarboxylic acid or with an inorganic polybasic acid;
lignin sulphonates; and, in particular
formaldehyde condensation products, e.g., condensation products of lignin sulphonates and/or phenol and formaldehyde; condensation products of formaldehyde with aromatic sulphonic acids, e.g., condensation products of ditolylethersulphonates and formaldehyde; condensation products of naphthalenesulphonic acid and/or naphthol- or naphthylaminesulphonic acids and formaldehyde; condensation products of phenolsulphonic acids and/or sulphonated dihydroxydiphenylsulphone and phenols or cresols with formaldehyde and/or urea; or condensation products of diphenyloxide-disulphonic acid derivatives with formaldehyde.
Depending on the type of compound of formula (1A) used, it may be beneficial to carry out the treatment in a neutral, alkaline or acidic bath. The method is usually conducted in the temperature range of from 20 to 140xc2x0 C.,for example at or near to the boiling point of the aqueous bath, e.g. at about 90xc2x0 C.
Solutions of the compound of formula (1A), or its emulsions in organic solvents may also be used in the method of the present invention. For example, the so-called solvent dyeing (pad thermofix application) or exhaust dyeing methods in dyeing machines may be used.
If the method of the present invention is combined with a textile treatment or finishing method, such combined treatment may be advantageously carried out using appropriate stable preparations which contain the compound of formula (1A) in a concentration such that the desired SPF improvement is achieved.
In certain cases, the compound of formula (1A) is made fully effective by an after-treatment. This may comprise a chemical treatment such as treatment with an acid, a thermal treatment or a combined thermal/chemical treatment.
It is often advantageous to use the compound of formula (1A) in admixture with an assistant or extender such as anhydrous sodium sulfate, sodium sulfate decahydrate, sodium chloride, sodium carbonate, an alkali metal phosphate such as sodium or potassium orthophosphate, sodium or potassium pyrophosphate or sodium or potassium tripolyphosphate, or an alkali metal silicate such as sodium silicate.
In addition to the compounds of formula (1A), a minor proportion of one or more adjuvants may also be employed in the method of the present invention. Examples of adjuvants include emulsifiers, perfumes, colouring dyes, opacifiers, further fluorescent whitening agents, bactericides, nonionic surfactants, fabric care ingredients, especially fabric softeners, stain release or stain repellant ingredients or water-proofing agents, anti-gelling agents such as nitrites or nitrates of alkali metals, especially sodium nitrate, and corrosion inhibitors such as sodium silicate.
The amount of each of these optional adjuvants should not exceed 1%, and preferably ranges from 0.01 to 1% by weight on the treated fibre.
The method of the present invention, in addition to providing protection to the skin, also increases the useful life of a textile article treated according to the present invention. In particular, the tear resistance and/or lightfastness of the treated textile fibre material may be improved.
The present invention also provides a textile fabric produced from a fibre treated according to the method of the present invention as well as an article of clothing produced from the said fabric.
Such textile fabrics and articles of clothing produced from the said fabrics typically have an SPF rating of 20 and above whereas untreated cotton, for example, generally has an SPF rating of from 2 to 4.
The treatment method according to the present invention may also be conducted by washing the textile fibre material with a detergent containing at least one compound of formula (1A), thereby imparting an excellent sun protection factor to the fibre material so washed.
The detergent treatment according to the present invention is preferably effected by washing the textile fibre material at least once with the detergent composition at a temperature ranging from 10 to 100xc2x0 C., especially from 15 to 60xc2x0 C.
The detergent composition used preferably comprises:
i) 5-90%, preferably 5-70% of an anionic surfactant and/or a nonionic surfactant;
ii) 5-70%, preferably 5-40% of a builder;
iii) 0-30%, preferably 1-12% of a peroxide;
iv) 0-10%, preferably 1-6% of a peroxide activator and/or 0-1%, preferably 0.1-0.3% of a bleaching catalyst;
v) 0.005-2%, preferably 0.01-1% of at least one compound of formula (1A); and
vi) 0.005-10%, preferably 0.1-5% of of one or more auxiliaries, each by weight, based on the total weight of the detergent.
The said detergent compositions are also new and, as such form a further aspect of the present invention.
The detergent may be formulated as a solid, as an aqueous liquid comprising 5-50, preferably 10-35% water or as a non-aqueous liquid detergent, containing not more than 5, preferably 0-1 wt. % of water, and based on a suspension of a builder in a non-ionic surfactant, as described, e.g., in GB-A-2158454.
The anionic surfactant component may be, e.g., a sulphate, sulphonate or carboxylate surfactant, or a mixture of these.
Preferred sulphates are alkyl sulphates having 12-22 carbon atoms in the alkyl radical, optionally in combination with alkyl ethoxy sulphates having 10-20 carbon atoms in the alkyl radical.
Preferred sulphonates include alkyl benzene sulphonates having 9-15 carbon atoms in the alkyl radical.
In each case, the cation is preferably an alkali metal, especially sodium.
Preferred carboxylates are alkali metal sarcosinates of formula R-CO(R1)CH2COOM1 in which R is alkyl or alkenyl having 9-17 carbon atoms in the alkyl or alkenyl radical, R1 is C1-C4 alkyl and M1 is alkali metal.
The nonionic surfactant component may be, e.g., a condensate of ethylene oxide with a C9-C15 primary alcohol having 3-8 moles of ethylene oxide per mole.
The builder component may be an alkali metal phosphate, especially a tripolyphosphate; a carbonate or bicarbonate, especially the sodium salts thereof; a silicate or disilicate; an aluminosilicate; a polycarboxylate; a polycarboxylic acid; an organic phosphonate; or an aminoalkylene poly (alkylene phosphonate); or a mixture of these.
Preferred silicates are crystalline layered sodium silicates of the formula NaHSimO2m+1.pH2O or Na2SimO2m+1.pH2O in which m is a number from 1.9 to 4 and p is 0 to 20.
Preferred aluminosilicates are the commercially-available synthetic materials designated as Zeolites A, B, X, and HS, or mixtures of these. Zeolite A is preferred.
Preferred polycarboxylates include hydroxypolycarboxylates, in particular citrates, polyacrylates and their copolymers with maleic anhydride.
Preferred polycarboxylic acids include nitrilotriacetic acid and ethylene diamine tetra-acetic acid.
Preferred organic phosphonates or aminoalkylene poly (alkylene phosphonates) are alkali metal ethane 1-hydroxy diphosphonates, nitrilo trimethylene phosphonates, ethylene diamine tetra methylene phosphonates and diethylene triamine penta methylene phosphonates.
Any peroxide component may be any organic or inorganic peroxide compound, described in the literature or available on the market, which bleaches textiles at conventional washing temperatures, e.g. temperatures in the range of from 5xc2x0 C. to 90xc2x0 C. In particular, the organic peroxides are, for example, monoperoxides or polyperoxides having alkyl chains of at least 3, preferably 6 to 20, carbon atoms; in particular diperoxydicarboxylates having 6 to 12 C. atoms, such as diperoxyperazelates, diperoxypersebacates, diperoxyphthalates and/or diperoxydodecanedioates, especially their corresponding free acids, are of interest. It is preferred, however, to employ very active inorganic peroxides, such as persulphate, perborate and/or percarbonate. It is, of course, also possible to employ mixtures of organic and/or inorganic peroxides. The peroxides, especially the inorganic peroxides, are preferably activated by the inclusion of an activator such as tetraacetyl ethylenediamine or nonoyloxybenzene sulfonate. Bleaching catalysts which may be added include, e.g., enzymatic peroxide precursors and/or metal complexes. Preferred metal complexes are manganese or iron complexes such as manganese or iron phthalocyanines or the complexes described in EP-A-0509787.
The detergents used will usually contain one or more auxiliaries such as soil suspending agents, for example sodium carboxymethylcellulose; salts for adjusting the pH, for example alkali or alkaline earth metal silicates; foam regulators, for example soap; salts for adjusting the spray drying and granulating properties, for example sodium sulphate; perfumes; and also, if appropriate, antistatic and softening agents; such as smectite clays; enzymes, such as amylases and proteases; photobleaching agents; pigments; and/or shading agents. These constituents should, of course, be stable to any bleaching system employed.